Granulator

ABSTRACT

A bell-shaped granulator container supported on lifting devices with a gas entry chamber circumferential of the base and connected to the base of the container through an annular gasentry gap. The container and its base enclose a stirrer, spraying device, comminuting tool and exhaust-gas filter.

[ Oct. 21, 1975 [56] References Cited UNITED STATES PATENTS 335,574 2/1886 Fuller et al. 241/57 2,309,036 1/1943 Beardsley................. 241/58 X Primary Examiner-Granville Y. Custer, Jr. Attorney, Agent, or FirmKarl W. Flocks [57] ABSTRACT A bell-shaped granulator container supported on lifting deviceswith a gas entry chamber circumferential of the base and connected to the base of the container through an annular gas-entry gap. The container and its base enclose a stirrer, spraying device, comminuting tool and exhaust-gas filter.

7 Claims, 2 Drawing Figures Inventors: Werner Glatt, Haltingen; Harm Siemer, Warendorf, both of Germany Assignee: Werner Glatt, Haltingen, Germany Apr. 5, 1974 Appl. No.: 458,428

Foreign Application Priority Data Apr. 5, 1973 Germany............... 2317129 US. Cl. 241/46.04; 241/46.17; 241/57 [51] Int. B02C 23/26 241/38, 46.04, 46.17, 47, 241/57, 58

United States Patent Glatt et al.

[ GRANULATOR [22] Filed:

[58] Field of Search I 1 I I I I I, Hi,

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GRANULATOR BACKGROUND OF THE INVENTION The invention relates to a granulator comprising an upright, round container, in whose lower region there is arranged an annular gas-entry gap of adjustable cross section and in whose upper region there is arranged a gas outlet, and comprising a spraying device.

Granulators of various kinds are employed mainly for converting various components, such as base materials and effective substances of medicines that are to be pressed into tablets but are present initially in the form of fine particles, into a granulate of coarser grain comprising homogeneous composition. As a preliminary stage of tablet-pressing, the purpose of the granulation is to produce a readily-flowing, compressible granulate, which is mixed in a given case with an external phase; e.g., a bursting or retarding agent and/or a lubricant before it is supplied to a tabletting press.

There is known a granulator of a type having some characteristics described above. Its upright-standing round container possesses a cylindrical main portion that tapers frustum-shaped upward toward a gas outlet and that tapers downward likewise frustum-shaped toward a point of narrowest cross section at which it widens again, frustum-shaped, further downward from such a point. This lowest frustum-shaped portion is connected in a downward direction to a cylindrical gasentry chamber, in which there ends a gas-entry pipe. In the lowest frustum-shaped widened portion and coaxially therewith, there is arranged a conical insert element, its tip pointing upward. Together with the wall of the lowest frustum-shaped widened portion, the insert element defines an annular gas-entry gap and is axially adjustable for changing the cross section of the gasentry gap. A pipe, which ends in a spraying nozzle arranged at the tip of the insert element, extends axially through the insert element. A material to be granulated, preferably suspended in a liquid, can be sprayed into the interior of the container through the spraying nozzle. During the injection of the material to be granulated, a working gas; e.g., heated air, is introduced through the annular gas-entry gap, all around the spraying nozzle likewise into the interior of the container. The adjustability of the gasentry gap makes it possible at any time to regulate the rate of the introduced gas in such a manner that the granulation cores or grains contained in the injected material are maintained in suspension, so that further components of the injected material can be deposited thereon. The separate grains of the granulate thus formed are pulled along upward by the gas flow at the center of the container and move again downward in the area of the container wall, in order to be finally discharged from the container through an outlet for the granulate.

In such granulators, the granulating material held in suspension by the gas flow in the container is designated as a fluidized bed or whirl layer. Accordingly, such granulators are called fluidized-bed or whirl-layer granulators.

The invention is based on the task of further developing a fluidized-bed or whirl-layer granulator of the type described at the outset in such a manner that it can be employed with greater versatility. Namely, it has turned out that substances which can be readily charged with static electricity cannot be granulated in known granulators of this kind, since the substances are deposited on the wall of the container. Besides, the granulators of the type described permit only the preparation of builtup granulates; i.e., granulates of more grainy structure and lesser density. However, for certain uses; e.g., as fertilizers, one requires agglomeration granulates; i.e., granulates of higher density, that can be shaped; e.g., into continuous-rod granulate, short-rod granulate or round pellets.

Agglomeration granulates are generally produced by mixing homogeneously the components of the granulates in a mixer, moistening with a granulating solution and kneading thoroughly. The moist mass is then brought into the desired granulate shape in a granulating machine. Finally, the granulating liquid employed for the aggregation is again evaporated in a drying device.

Until the present time it seemed that the various processes and devices for the preparation of built-up granulates, on the one hand, and agglomeration granulates, on the other hand, could not be combined with each other.

SUMMARY OF THE INVENTION However, the invention provides as solution of the task described, in a granulator of a type discussed above, that the container should consist of a bottom plate comprising a stirrer and a bell-shaped, downwardopen container upper part, which can be lifted from the bottom plate by means of a lifting device, and that the annular gas-entry gap be formed between the lower edge region of the container upper part and the bottom plate, when the container upper part is lifted, which gap is closed when the container upper part is lowered.

The granulator of the present invention allows not only the control of the granulating operation through lifting and lowering of the container upper part, but also provides the possibility of a choice between two working positions that are fundamentally different from one another from the viewpoint of process engineering.

When the container upper part is lowered to the full extent, its lower edge region rests on the bottom plate, so that the container is closed. The ordinary agglomeration granulates can be produced in this connection with the stirrer as the components mixed together with the stirrer and moistened by the spraying device are either supplied to a separate granulation machine or dried in the container of the granulator itself for which purpose a gas-entry gap is formed by lifting the upper part of the container and heated air is supplied through such a gap for drying the granulate.

On the other hand, if a gas, preferably heated air, is supplied to the intermixed components already at the start of the injection of a granulating solution, abuiltup granulate is formed, which granulate corresponds in its structure to granulates formed in a whirl-layer or in a fluidized-bed. V

In order to move and'dry the intermixed components of the granulate to be formed, the granulatorof the invention requires a gas flow which is merely weak in comparison with known whirl-layer granulators, owing to which a smaller amount of particles is pulled alongfrom the granulate and, consequently, the service life of the filters ordinarily arranged in front of the gas out let is extended.

The possibility of producing and drying agglomeration granulates in a closed system also provides particularly favorable conditions from the viewpoint of hygiene. Accordingly, the granulator of the invention is particularly suitable for producing materials of low germ-content, as hot air is supplied initially, while the stirrer is running and the gas-entry gap is opened, until the material attains the required temperature and the amount of air passed through the container is then reduced and a germ-destroying gas; e.g., ethylene oxide, is supplied to the feed air.

When the container upper part of the granulator of the invention is lifted to a certain extent from the bottom plate, the surrounding air can be induced to flow with a certain intensity into the container through the annular gas-entry gap by attaching a suction blower to the gas outlet. However, in the case where one does not work with the surrounding air but with another gas; e.g., heated air, a preferred embodiment provides that the lower edge region of the container upper part be enclosed by an annular gas-entry chamber, that can be connected to a hot-air blower, a gas pipe or the like.

The latter described embodiment can be arranged in such a manner that the upper part of the container is guided like a piston in a cylindrical top piece of the bottom plate, which top piece defines the gas-entry chamber in an outward direction.

Another embodiment consists in that the upper part of the container is connected to the bottom plate by means of an elastic annular wall defining the gas-entry chamber in an outward direction.

In any case it is of advantage to have the lower edge region of the container upper part project radially inward, so as to form a guide surface conducting the gas flow in an inward direction.

A spraying device is expediently arranged on the upper part of the container and oriented toward the bottom plate.

Finally, it may be of advantage in some cases to have a rotary-driven comminuting tool mounted on the upper part of the interior of the container.

BRIEF DESCRIPTION OF THE DRAWING The invention is explained with further details in the following text by means of schematic drawings showing an exemplified embodiment wherein:

FIG. 1 shows a vertical axial section through a granulator of the invention; and

FIG. 2 shows an enlarged sector of FIG. 1 with modified details.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the granulator shown therein possesses a container consisting of a bottom plate and an upper part 12 of the container. Container upper part 12 consists of a substantially cylindrical base part 14, which tapers frustum-shaped in its upper region, a cylindrical central part 16 and a filter part 18, which is likewise cylindrical and closed at the top. These parts are arranged coaxially one above the other and bolted to each other. The container upper part formed in this manner has the shape of a bell.

Base part 14 has a lower edge region 20, which projects radially inward, its lower face forming a guide surface for the gas flowing into the container. Above edge region 20, base part 14 is provided with a radially outward-projecting flange 22, engaged by a lifting device 24. In the example illustrated, lifting device 24 consists of three hydraulic or pneumatic pistoncylinder units hinged to flange 22 at equal peripheral intervals.

A shaft 26 extends substantially radially through the wall of base part 14, above flange 22, a comminuting tool 28 being attached to its inner end. Shaft 26 is mounted in a bearing block 30 attached to the wall of base part 14 and connected by means ofa belt drive 32 to an electric motor 34 attached to the same wall. Finally, in its upper portion which tapers frustum-shaped, base part 14 is provided with a material inlet 36 for the material to be granulated.

A spraying device 38 is arranged in central part 16. It is a sprayer or sprinkler, of single or multiple nozzle and is provided for spraying a granulating liquid, such as for example, a gelatine solution, in a downward direction.

Filter part 18 is provided with an exhaust-gas filter 40 and, above that, a gas outlet 42.

A stirrer 44 is arranged directly above bottom plate 10. It is shown as a multiblade propeller and attached to a shaft 46, which extends vertically and substantially coaxially with container upper part 12, downward through bottom plate 10, and is coupled to an electric motor 48, possibly by means of an infinitely variable gearing that is not illustrated. A number of materialoutlet openings 50 for the granulated material are arranged in bottom plate 10 around stirrer 44. Materialoutlet openings 50 can be closed by means of an apertured shutter 52 pivoted on the lower side of bottom plate 10. A hand lever 54 is provided for turning apertured shutter 52. Material-outlet openings 50 end in a funnel 56. Finally, the bottom plate is provided with at least one gas inlet 58 radially outside lower edge region 20 of container upper part 12. A plurality of these gas inlets is preferably arranged at equal annular intervals around lower edge region 20. As previously mentioned, hot air or surrounding air and additionally ethylene oxide may flow into the container through gas inlet 58.

The above description is true jointly for the embodiments shown in FIGS. 1 and 2. Now, a particular feature of the embodiment of FIG. 1 consists in that a cylindrical top piece 60 is attached in gas tight manner such as by welding to bottom plate 10 at a radial distance outside lower edge region 20 of container upper part 12. Top piece 60 is sealed in relation to flange 22 of container upper part 12 by means of a ring-diskshaped packing 62 attached to the flange. The pistoncylinder units of lifting device 24 are hinged to the upper side of flange 22, on the one hand, and in each case to a support 64 attached to bottom plate 10, on the other hand. Entire container upper part 12 is thus suspended, swinging like a pendulum, so that ring-diskshaped packing 62 contacts top piece 60 providing a seal all around, without being subjected to a considerable. radial pressure in any position.

In the embodiment illustrated in FIG. 2, bottom plate 10 is connected in gas-tight manner to flange 22 of container upper part 12, by means of an elastic annular wall 66, radially outside gas inlet 58 or a ring of such gas inlets. The piston-cylinder units, that constitute lifting device 24 also in this case, are hinged to the bottom plate, on the one hand, and, on the other hand, to the lower side of flange 22 which is widened in radial direction beyond elastic annular wall 66. Accordingly, in

' this embodiment the container upper part is supported from below. Radial displacements of container upper part 12 are prevented through at least three guide extensions 68 attached to bottom plate 10, lower edge region 20 of container upper part 12 being guided with small radial play between said extensions.

in the two embodiments, shown in FIG. 1, on the one hand, and FIG. 2, on the other hand, a gas-entry chamber 70 is formed through the described features around lower edge region 20 of container upper part 12, which chamber can be supplied through gas inlet 58 with a working gas under pressure; e.g., hot air. When lifting device 24 is actuated in the manner illustrated so that container upper part 12 is lifted from bottom plate by a small amount, of the order of magnitude extending from one millimeter to one centimeter or a few centimeters, an annular gas-entry gap 72 is formed between bottom plate 10 and lower edge region 20. The working gas flows through the said gap from the gas-entry chamber from all sides radially into the container and upward through material 74 situated in the container, in order to escape finally from the container through exhaust-gas filter 40 and gas outlet 42. Portions of material 74 hurled radially outward by stirrer 44 are pulled upward by the working gas in this connection, so that a fluidized bed is formed. Even when the gas-entry gap is so narrow and/or the gas pressure in gas-entry chamber 70 is so low that no proper fluidized bed can be formed in the container, the inflowing working gas contributes to the elimination of dead zones in the container, so that material 74 can be thoroughly stirred by stirrer 44.

The granulator according to the invention is operated preferably with intermittent operation. Upon the beginning of each operation cycle the container 12 has its lowermost position, where the base member 14 rests with its edge region on the bottom plate 10 so that the gas-entry gap 72 is closed. The material-outlet opening 50 are likewise closed. Through material inlet 36 a charge of material 74 is supplied to the base member 14. Then the material inlet 36 is closed and a gas, for instance surrounding air, is fed into the gas-entry chamber 70 through gas inlet 58. At the same time, or a little later, upper portion 12 of the container is lifted a smaller or larger distance by means of the lifting device 24 so that an annular gas-entry gap 72 having a more or less large cross section is produced. While entering gas flows through material 74, this material can be stirred, if desired, in addition by stirrer 44. During a first phase of the stirring of material 74 caused by the inflowing gas alone or in conjunction with stirrer 44, the material is sprayed by means of the spraying device 38 with a granulating liquid, for instance a gelatine solution. After a predetermined time has lapsed the supply of granulating liquid is discontinued and the material 74 is continued to be stirred by a gas entering through the annular gap 72 and, if necessary, in addition by the stirrer 44. The gas which is preferably hot air in a second phase of each operation cycle dries material 74 and is vented at the upper portion 12 of the container through gas outlet 42, after having passed through the exhaust-gas filter 40.

As soon as the desired granulate has been formed from material 74 the upper portion 12 of the container is lowered again to the bottom plate 10. At the same time or shortly thereafter the material outlet openings 50 are opened by turning apertured shutter 52 so that the material flows into the funnel 56 partly due to its own gravity and partly as a consequence of the action of the continued rotation of stirrer 44. The material outlet openings are then'again closed and a new operation cycle can start.

If desired, the comminuting device 28 can be operated in certain phases of each operation cycle, especially before or during the spraying of granulating liquid 'by means of spraying device 38.

The finished granulated material 74 can be filled for example into a container from funnel 56.

It will be obvious to those skilled in the art that various changes may be made without departing from the scope'of the invention is not to be considered limited to what is shown in the drawings and described in the specification.

What is claimed is:

l. A granulator comprising a container having a bell-shaped, downward-open container upper part and a bottom plate beneath the opening under said container upper part,

a stirrer arranged above said bottom plate,

lifting means to lift said container upper part from said bottom plate,

a gas outlet in the upper portion of said container,

means to supply gas to said container including an annular gas-entry gap of adjustable cross-section formed between a lower-edge region of said container upper part and said bottom plate when said container upper part is lifted by said lifting means and which said gap is closed when said container upper part is lowered by said lifting means,

and a spraying device within said container.

2. The granulator of claim 1, further characterized by said means to supply gas to said container further including an annular gas-inlet chamber enclosing the loweredge region of said container upper part.

3. The granulator of claim 2, further characterized by said bottom plate having a cylindrical top piece defining said annular gas-inlet chamber on its outward side and guiding said container upper part therein.

4. The granulator of claim 2, further characterized by an elastic annular wall connected between said container upper part and said bottom plate and defining.an outer wall of said gas-inlet chamber.

5. The granulator of claim 1, further characterized by said lower-edge region of said container upper part projecting radially inward and forming a guide surface which conducts the gas flow in an inward direction.

6. The granulator of claim 1, further characterized by said spraying device arranged on the inside of said container upper part and oriented toward said bottom plate.

7. The granulator of claim 1, further characterized by a comminuting tool which is rotatable, mounted on said container upper part. 

1. A granulator comprising a container having a bell-shaped, downward-open container upper part and a bottom plate beneath the opening under said container upper part, a stirrer arranged above said bottom plate, lifting means to lift said container upper part from said bottom plate, a gas outlet in the upper portion of said container, means to supply gas to said container including an annular gasentry gap of adjustable cross-section formed between a loweredge region of said container upper part and said bottom plate when said container upper part is lifted by said lifting means and which said gap is closed when said container upper part is lowered by said lifting means, and a spraying device within said container.
 2. The granulator of claim 1, further characterized by said means to supply gas to said container further including an annular gas-inlet chamber enclosing the lower-edge region of said container upper part.
 3. The granulator of claim 2, further characterized by said bottom plate having a cylindrical top piece defining said annular gas-inlet chamber on its outward side and guiding said container upper part therein.
 4. The granulator of claim 2, further characterized by an elastic annular wall connected between said container upper part and said bottom plate and defining an outer wall of said gas-inlet chamber.
 5. The granulator of claim 1, further characterized by said lower-edge Region of said container upper part projecting radially inward and forming a guide surface which conducts the gas flow in an inward direction.
 6. The granulator of claim 1, further characterized by said spraying device arranged on the inside of said container upper part and oriented toward said bottom plate.
 7. The granulator of claim 1, further characterized by a comminuting tool which is rotatable, mounted on said container upper part. 